Let's just talk about merits and demerits of the deal and the strategic alliance. This deal comes with lot of baggage.
India has to change its foriegn policy stand even before the deal was signed: "Voting against Iran in nuclear security issue". US congressman and Senator openly warned India to vote againt Iran if we want the deal to complete. This is atrocious; these petty politicians threatening our great nation.
Also, India has no enmity against Iran. Actually, we have had very good relationship with them. Iran is the only country which kind of vetoed the resolution, moved by pakistan, condemning India in OIC [organuzation of Islamic countires conf] some 20 years ago. It even gave permission for India to use its airspace and land incase of war with Pakistan. why should we vote against a friend?
This is just the beginning and we will lose much more than what we gain from this alliance.
Agreed, nuclear energy is important but we have other options and US is not only way to go.